Thrilling that a planet of Earthlike mass has been found at Alpha Centauri, but it's disappointing that it's super-close to its star and super-hot. Still, it proves we have the tools to find other Earth-sized planets in the system, so hopefully it won't be long until we know what else is there.

At 6 million km (25 times closer than 1 AU to a star that's 50% of the sun's brightness), I'd guess the surface temperature is somewhere around 1600 F, though the 6 million km figure probably includes quite a large error bar.

"The European team detected the planet by picking up the tiny wobbles in the motion of the star Alpha Centauri B created by the gravitational pull of the orbiting planet [2]. The effect is minute — it causes the star to move back and forth by no more than 51 centimetres per second (1.8 km/hour), about the speed of a baby crawling. This is the highest precision ever achieved using this method."

I bet there are a few more zipping around Alpha C. Yesterday, before this news I read @ space.com about KOI-500 which appears to have five planets orbiting all closer than Mercury. Been waiting for news about Alpha Centauri, always hoped planets would be found there.

By this point, it's fairly safe to assume, though as yet scientifically impossible to conclude, that pretty much EVERY star will have one or more (probably more) planetary bodies around it. The race IMO should shift to determining valid ways of finding actual Earth-size, atmostphere-bearing planets within a star's potential Goldilocks zone. We are discovering planets almost weekly now, through analysis of passive observation, which is great. I would love for a breakthrough to be made in detecting planets like ours, which then puts us a step closer to potentially habitable worlds.

The race used to be about finding out what's there; I think we should be looking to find places for humans to ultimately go to.

^ I disagree. I think the race should be coming up with better imaging techniques capable of locating objects that DO NOT cause a detectable wobble in their parent star, or whose effect might be totally overwhelmed by other objects in their system.

This, incidentally, is why we only ever seem to find planets in really odd positions -- ridiculously close to their star or planets of unusual size. Meanwhile, we could spot a carbon copy of our own solar system and never be able to detect anything smaller than Jupiter orbiting it; the other seven planets would be undetectable, and worse still if this system has two or more dwarf planets in the goldilocks zone.

Since it can be safely assumed that almost every star in the milky way has at least one planet, we should focus our efforts on increasing our detection threshhold so that we can locate smaller objects in wider orbits, possibly allowing for planet searches around some of brighter/hotter/bigger stars with absurdly huge habitable zones (hell, maybe giant Betelgeuse has a couple of Earthlike planets in hundred-year orbits or spinning around a neptune-sized gas giant; I imagine that Europa and/or Titan would become pretty nice places to live during the Sun's red giant phase).

I feel that we are in the infancy stage of planet detecting. I believe in time that we will be able to spot planets that are further out. However, I do believe that we will have gaps in our information about each system until we get the means to visit the system, either manned or unmanned, and do a physical count.

^We'll have the technology to image exoplanetary systems in detail long before we have the technology to travel there. The James Webb Space Telescope, which is under construction now and should be launched by the end of the decade if government funding holds up, would probably be able to detect planets around Alpha Centauri by imaging them directly. And there are ideas for more advanced telescopes that could achieve even more. By travelling out to the Sun's gravitational focus, the focal point of the Sun's gravity-lensing effect about 550 AU out, we could make the Sun itself into a huge telescope with such high resolution that we could make detailed maps of any planets around Alpha Centauri, maybe even discern individual objects the size of cars, although that's perhaps an optimistic assessment.

The problems to surmount in order to actually reach other star systems are exponentially greater than the problems to surmount in order to image them in detail from right here in the Solar System. Science fiction tends to gloss over the difficulties of space travel as a dramatic convenience, but we mustn't let it mislead us about the enormous obstacles that civilization as a whole would have to surmount to traverse the vast distances between stars.

Here's a bizarre point to ponder, assuming a universe where we can build enormous telescopes (many, many miles in diameter) but where interstellar journey's remain problematic.

In theory the surface of a neutron star is smooth almost to the atomic level, due to the intense gravity. A surface that smooth is often a mirror. If there are some neutron stars whose surface atoms are still normal enough for conventional electron shells, the star would be a spherical mirror like the ones you see at the corners of supermarkets and fork truck areas, where you can look at the mirror and see in all directions.

If we had a big enough telescope that could see one of these neutron stars located hundreds or thousands of light-years away, you'd have a way to reconstruct the image seen from that neutron star and gain a huge baseline for parallax measurements. If the neutron star was above the galactic plane, perhaps near a globular cluster, you could get an image of our own galaxy taken from outside it.

But the telescope to capture such an image would, indeed, be enormous! Quite a few "if's" in there, but it is at least an unusual thought.

^The resolution would be way too low, and there'd be too much light extinction due to interstellar gas and dust. Also, keep in mind that you need a concave mirror to focus the image in a reflecting telescope. Even if a neutron star surface were a perfect mirror, it would be a convex, spherical one. Most of the light impinging on it from Earth would be spread outward, not focused back at us.

Not to mention that a neutron star's surface might well be covered in cracks and subject to seismic activity, not as perfectly smooth as one might think. And it would be spinning rather fast. (So maybe kinda like a disco ball?) Not to mention that most neutron stars would be hot enough to incandesce, and that light would probably wash out any reflections.

Since it can be safely assumed that almost every star in the milky way has at least one planet, we should focus our efforts on increasing our detection threshhold so that we can locate smaller objects in wider orbits, possibly allowing for planet searches around some of brighter/hotter/bigger stars with absurdly huge habitable zones (hell, maybe giant Betelgeuse has a couple of Earthlike planets in hundred-year orbits or spinning around a neptune-sized gas giant; I imagine that Europa and/or Titan would become pretty nice places to live during the Sun's red giant phase).

Click to expand...

Only if they were to have atmospheres we could actually breathe by then...

Mind you, in 2-3 billion years, we should hopefully have gone elsewhere or evolved to some state where it wouldn't matter to us.

^The resolution would be way too low, and there'd be too much light extinction due to interstellar gas and dust. Also, keep in mind that you need a concave mirror to focus the image in a reflecting telescope. Even if a neutron star surface were a perfect mirror, it would be a convex, spherical one. Most of the light impinging on it from Earth would be spread outward, not focused back at us.

Not to mention that a neutron star's surface might well be covered in cracks and subject to seismic activity, not as perfectly smooth as one might think. And it would be spinning rather fast. (So maybe kinda like a disco ball?) Not to mention that most neutron stars would be hot enough to incandesce, and that light would probably wash out any reflections.

Now we know that there is a potential to use the sun itself as a gravitational lens--and you don't just get a focal point--but a focal line--so it is good to keep an open mind. Maybe not a mirror--but a lens is doable from our own star 400-800 AU out, which is more do-able than true interstellar travel for now.

Now I want to know how this might apply to beamed energy propulsion--since you have a focal line.